Precise metabolic phenotyping depends significantly on the health status of animal subjects. Stable housing and husbandry and microbiological testing minimize the influence of exogenous factors that could impact phenotyping results. The rigors inherent to quarantine and testing mice to ensure acceptable health status must be balanced with the need to expedite phenotyping of newly arrived mice. The Animal Core will provide state-of-the-art husbandry, health care, quarantine, testing, and procedure space for assessing mice submitted to the Mouse Metabolic Phenotyping Center (MMPC). The Animal Care Core has implemented an expedited quarantine program that has been effect for the past 9 years. This has successfully decreased the quarantine time and allowed phenotyping to begin while animals are within quarantine, allowing animals to be studied at younger ages and minimizing costs associated with the phenotyping process. The Core will: 1) import mice for metabolic phenotyping, 2) determine the microbiological profile of each imported cohort and provide the Center Director with interpretation and advice about the results, 3) provide stable, biocontainment housing, husbandry and health care for mice submitted to the Center, 4) provide a dedicated, biosecure suite of room for quarantine, housing and on-site phenotyping procedures, 5) perform morphological phenotyping as requested, 6) provide to Center clients results and advice on the health status of submitted mice. The facilities include 600 ft^ of dedicated biocontainment housing and procedure space equipped with 160 cage ventilated rack, an NMR analyzer, and 8 metabolic (calorimetry) cages. The core is expected to import 802 +/- 215 mice per year, based on core volume during the previous 5 years.